1. Technical Field
The present invention relates to the technical fields of a vehicle body structure that is equipped with an onboard battery including a housing case and a battery module housed in the housing case and of the onboard battery.
2. Related Art
Onboard batteries are installed in various vehicles, such as automobiles, in order to supply electric power to motors and other various electrical components. In recent years, in particular, vehicles such as electric vehicles (EV), hybrid electric vehicles (HEV), and plug-in hybrid electric vehicles (PHEV) have gained widespread use. In these electricity-driven vehicles, onboard batteries having a high electricity-storage function are installed.
An onboard battery includes a housing case and a battery module housed in the housing case. The battery module is configured by, for example, arranging a plurality of battery cells (secondary batteries), such as nickel hydrogen batteries or lithium ion batteries. In some onboard batteries to be installed in an electric vehicle or the like, in order to retain a high electricity-storage function, a plurality of battery modules are disposed in the housing case and battery cells in each of the battery modules are coupled in series or in parallel.
An example of such an onboard battery is disposed in a trunk formed in a rear part of a vehicle (see Japanese Patent No. 5206110).
The onboard battery described in Japanese Patent No. 5206110 is located between rear side frames of a vehicle body, which are provided apart from each other in the transversal direction, the onboard battery being partly inserted into a disposition depression having an upward opening in a floor panel.
In a vehicle equipped with the onboard battery described in Japanese Patent No. 5206110, the onboard battery is disposed in the front side of the trunk, and a space behind the onboard battery in the trunk is formed as a crushable area. Accordingly, when a load is applied from behind by collision from behind the vehicle, the pair of rear side frames is crushed to absorb a shock, so that the onboard battery is protected.
On the other hand, in the vehicle equipped with the onboard battery described in Japanese Patent No. 5206110, if collision from behind the vehicle is severe, there is a possibility that the rear side frames are crushed and also a large load is applied from behind to the onboard battery. When a load is applied to the onboard battery, an inclined part of the housing case is guided to a front surface part forming the disposition depression, and the entire onboard battery is moved diagonally up-forward so as to avoid a cross-member located in front of the disposition depression. Accordingly, the onboard battery does not collide with the cross-member, which suppresses an excessive load to a battery module housed inside the housing case.
However, if the vehicle in which the onboard battery is disposed on the front side of the trunk as described in Japanese Patent No. 5206110 is involved in a severe collision, the entire onboard battery is moved diagonally up-forward. Hence, there is a possibility that part of the housing case comes into contact with a portion with high rigidity in the vehicle body, such as a portion where a seat hinge bracket supporting a turning shaft of rear seats and the floor panel are coupled to the cross-member.
When part of the housing case comes into contact with such a portion with high rigidity, the housing case may bend at the contact portion as an origin. This may damage the housing case, and damage or break each component disposed inside the housing case.
As an example other than a collision from behind the vehicle, if a rear part of the vehicle equipped with the onboard battery collides with a telegraph pole etc. due to spin or the like (i.e., if so-called pole collision occurs), a portion between a pair of rear side frames in the vehicle body collides with the telegraph pole etc. in some cases. In this case, the telegraph pole etc. applies a large load to the onboard battery to move the entire onboard battery diagonally up-forward; thus, part of the housing case may come into contact with a portion with high rigidity, so that the housing case may bend at the contact portion as an origin. This may damage the housing case, and damage or break each component disposed inside the housing case.